The low-level graphics product is a forecast of aviation weather
hazards, primarily intended to be used as a guidance product for
briefing the VFR pilot. The forecast domain covers the 48 contiguous
states, southern Canada and the coastal waters for altitudes below
24,000 ft. Low altitude Significant Weather charts are issued four
times daily and are valid at fixed times: 0000, 0600, 1200, and 1800
UTC. Each 4 panel chart is divided on the left and right into 12 and
24 hour forecast intervals (based on the current ETA model available).
The upper two panels (SIG WX PROGs) depict freezing levels,
turbulence, and low cloud ceilings and/or restrictions to visibility
(shown as contoured areas of MVFR and IFR conditions). The lower two
panels (SFC PROGs) are provided by the Weather
Prediction Center (WPC) and consist of graphical displays of
fronts and precipitation areas.

This legend appears on the 4 panel chart and applies to the upper
(SIG WX PROG) charts. It has been removed from the individual color
charts.

This legend appears on the 4 panel chart and applies to the lower
(SFC PROG) charts. It has been removed from the individual color
charts.